Tetrodecamycin and dihydrotetrodecamycin, new antimicrobial antibiotics against Pasteurella piscicida produced by Streptomyces nashvillensis MJ885-mF8. II. Structure determination.

Novel antimicrobial antibiotics against Pasteurella piscicida, tetrodecamycin (1) and weakly active dihydrotetrodecamycin (2) were isolated from a culture broth of Streptomyces nashvillensis MJ885-mF8. The planar structure of 1 was determined to be 2-acyl-4-ylidene tetronic acid alkyl ether containing decaline ring by various NMR spectral data of 1 and its acetyl derivative (3). The structure of 2 was elucidated by comparison with the spectral data of 1 and confirmed by catalytic reduction of 1 into 2. The X-ray crystallography of 2 showed the relative stereochemistry. Their absolute configurations were determined by using modified Mosher's method.